Earl’s 501ERL oil thermostat is a billet 6061‑T6 aluminum housing thermostatic valve designed to regulate engine oil temperature. It bypasses the oil cooler until oil temperature reaches 160 °F, gradually opening and achieving full flow by 180 °F. Compatible with –10 AN hoses/fittings and features three 1/8″ NPT sensor ports for oil temperature, flow, and pressure monitoring. Ideal for automotive, marine, and cold-climate applications using external oil coolers .